Inhibition of thermal degradation of mackerel surimi by pig plasma proteinand L-kininogen

Use of purified L-kininogen to prevent actomyosin (AM) degradation by cathe psins, and pig plasma proteins to reduce mackerel modori were investigated. Myosin heavy chain (MHC) degradation in AM containing various cathepsins w as significantly inhibited by purified L-kininogen. The texture of mackerel gel increased to 2-fold and 1.7-fold in breaking force (g) and deformation (cm) separately after adding 1% pig plasma protein. SDS-PAGE showed that d egradation of MHC in mackerel surimi was significantly reduced after 1% pig plasma protein addition at several temperatures. It suggested that the pig plasma protein containing L-kininogen could effectively reduce the modori phenomenon of mackerel surimi during processing.